New Zealand's education system has been treading water and its students will lose out in the global race for the best jobs unless change is embraced, a visiting expert warns.

Andreas Schleicher has been dubbed "the world's schoolmaster" by international media - and he advises a shake-up of New Zealand's system.

The German scientist and statistician is a pioneer of using hard data to analyse what was traditionally thought of as a "soft" subject, previously dominated by tradition, theories and ideology.

The change in approach helped him become one of the world's most influential education experts.

Arne Duncan, United States President Barack Obama's Secretary of Education, regularly seeks the counsel of Mr Schleicher, now the deputy director of education at the Organisation for Economic Co-operation and Development (OECD).

Education Minister Hekia Parata is a fan too, and is hosting him in New Zealand this week.

That is no surprise as, during the interview with the Herald, Mr Schleicher says he backs some of the National Party's more controversial initiatives such as National Standards.

His reasoning for change is that while New Zealand has a very good education system, if compared internationally its performance over the past 10 years has plateaued.

"Every country is improving, but the pace of change varies. And we can only see that when we look at ourselves in the mirror of what everybody else is achieving."

That kind of international comparison hardly existed when Mr Schleicher joined the OECD in 1994.

"I remember the first meeting of OECD ministers that I attended. There were 26 ministers sitting around a table there, and everybody was saying, 'I've got the best education system in the world'," he recalls.

"I come from a field of physics where knowledge is globalised - if I make an invention, everybody is going to know about it, and everybody is going to work on that basis.

"Knowledge in education is very sticky - you don't get it out of the schools, you don't get it from one system to the next."

Mr Schleicher and his colleagues designed a test which would help the OECD measure how much children learn in different countries, not just inputs such as total education spend.

Now 15-year-olds from more than 70 countries and economies take part in the Programme for International Student Assessment (PISA), which measures not just retention of facts but the ability to think critically and solve problems.

The first set of results shocked many countries. The US found itself well outside the top 10, and Germany, which had considered its system among the best in the world, ranked even worse.

In the latest 2009 results, New Zealand was ranked 13th in maths and seventh in both reading and sciences.

But Mr Schleicher says PISA is not about rankings, but identifying what others do well and what works.

Analysis shows poor kids in Finland, Canada and Shanghai do far better relative to their more privileged peers than poor kids in New Zealand and other countries.

"When people tell me, 'social background is a driver of success, it is always going to be like this', I can say now, 'Yes, it is true. But it is true to a very different extent in different systems around the world,"' Mr Schleicher says. So, what insights can he and his data offer New Zealanders?

Parents

A parent questionnaire which ran with the PISA test was used to see what factors were most important in terms of test results.

It found that parents showing a consistent interest in a child's education is the most important factor in raising his or her achievement.

"It is not the hours of homework that you spend with your children, it is not about the degree that you have," Mr Schleicher says. "It is simple things - when parents ask them every day at the dinner table, 'How was school? What went well? Did you have any difficulties?"'

Teachers

New Zealand must deploy its best teachers to the most challenging classrooms, Mr Schleicher says. Data clearly show the highest performing countries prioritise and target the quality of teaching.

Overseas examples include Shanghai, which topped the 2009 results, where vice-principals at successful schools can only become principals if they show they can turn around one of the lowest-performing schools.

And Finland turned around its poor educational standards in the 1960s and'70s by making teaching a high-status profession, like law.

Mr Schleicher says most important is to make teaching more diverse and challenging - a 25-year-old mathematics teacher will not relish the prospect of being in the same classroom in 15 years, for example.

"The key is to create perspectives for people to grow in their careers - to take on tougher challenges, and move up by showing they can make a difference."

Schools

A particular challenge for New Zealand is that many of the worst-performing students are at the same schools as the best, Mr Schleicher says.

Making learning more personal - and moving away from one-size-fits-all teaching - should be the response.

While social factors unquestionably affected achievement, some schools in disadvantaged areas did much better on the PISA test.

The reasons for that needed to be shared across schools, Mr Schleicher says. "The solutions are in New Zealand. But they need to be universal."

National standards

Mr Schleicher supports National Standards data as a way for educators to identify success and failure.

The standards are descriptions of what students should be able to do in reading, writing and mathematics as they progress through levels 1 to 8, the primary and intermediate years.

Their introduction has been controversial, with opponents saying they will lead to "league tables" of schools, and give parents the false impression that a school can be judged by its results alone. "I can see the challenges," Mr Schleicher says.

"But in the dark all schools look the same, and all students look the same.

"Unless you have some light to illuminate the differences, there is very little you can do about it."

Charter schools

Overseas evidence suggests the Government shouldn't bother with its plans for charter - or "partnership" - schools, Mr Schleicher says.

Mrs Parata will confirm the operators of the first schools, which will be publicly funded but privately operated, by next month, with up to five set to open next year.

"In New Zealand, once you account for social background, there is no difference between public and private schools. If you do that around the world, there is no difference between charter and public schools," Mr Schleicher says.

"In fact, there is typically more variability in quality in charter schools ... I really don't think charter schools are a magic bullet ... the bottom line is, there isn't much measurable advantage."